The present invention is directed to a method for automating the placement of a faceplate in a hearing instrument using rule-based protocols based on characteristic shell features and collision detection protocols.
The envisioned faceplate placement protocols use impression features obtained from a mold 10 (FIGS. 1A-1C) of the ear canal meatus and external ear. Using principal component analysis (PCA) techniques, characteristic features of the impression, such as the tragus 18, anti-tragus 14, and anti-helix 26 are clearly demarcated. Furthermore, optimization techniques such as genetic algorithm, stochastic optimization, memetic algorithm, and/or general combinatorial optimization algorithms are also key algorithmic candidates for the determination of impression features within wide demographic population. FIG. 2A illustrates definitive landmarks for a datum plane of an impression 10. FIGS. 2B and 2C illustrate corresponding portions of a human ear and impression made therefrom.
A typical in-the-ear (ITE) hearing instrument comprises the following key electronic components:                A microphone that picks up the sound and transfers it to the amplifier;        A receiver that makes the sound louder and helps correct any sound distortion;        A volume control that adjusts loudness;        A battery that supplies the power; and        A push button that toggles between programmed settings.        
In a traditional hearing aid design, the shelf 10′ of the hearing aid undergoes a number of manual and labor-intensive operations in a multi-process procedure. These processes occur in order to reduce a raw impression 10 to a prescribed hearing aid instrument.
One stage of this multi-process procedure is the interactive placement of the faceplate. This is initiated virtually in order to a priori determine whether the prescribed device can be built for the given impression. Furthermore, the final position of the faceplate is considered that which is most optimum, anatomically more comfortable, and collision free (meaning that it does not interfere with electronic components or other parts of the shell).
All hearing instruments have electronic components, such as batteries, a microphone, a push button(s), a volume control, hybrids, programming contacts, and a faceplate which serves as a carrier for these components. Due to the anatomy of the ear canal, some protruding electronic components, such as the pushbuttons and volume controls, have to be positioned such that they so not come into contact with the patient's ear. Hence significant effort is undertaken during the design phase of the casing of the hearing instrument to ensure that patient comfort is accounted for.